Outbreak of Multiply Drug-Resistant Proteus mirabilis Originating in a Surgical Intensive Care Unit: In Vitro Susceptibility Pattern

Abstract

A multiply drug-resistant strain of Proteus mirabilis was isolated from 14 patients on a surgical service. Antimicrobial susceptibility studies demonstrated that the organism was highly resistant to numerous antibiotics, including gentamicin, tobramycin, and sisomicin. The organism was susceptible in vitro to amikacin but had low-level resistance to netilmicin. In vitro susceptibility studies with combinations of cephalothin with netilmicin and trimethoprim with sulfamethoxazole showed these drugs to be synergistic. Other drug combinations failed to act synergistically.

Identification of Tn2401, a Transposon Encoding Multiresistance to Aminoglycosides

“…Aminoglycoside antibiotics such as gentamicin, tobramycin, sisomicin, dibekacin, and amikacin are still of great importance in the treatment of life-threatening infections, but there are many reports of serious infections caused by aminoglycoside-resistant Enterobacteriaceae and Pseudomonas strains in hospitals (Acar et al, Yoshikawa et al, 1978). In clinical isolates resistance to aminoglycoside-aminocyclitol antibiotics is usually associated with the presence of enzymes that catalyse N-acetylation, O-phosphorylation, or O-adenylylation of amino or hydroxyl groups on the drug molecule (Beneviste & Davies, 1973).…”